Loop takers for sewing machines



Oct. 31, 1961 R. E. JOHNSON LOOP TAKERS FOR SEWING MACHINES 2 Sheets-Sheet 1 Filed Aug. 28, 1958 i Q; INVENTOR.

RALPH E. JoH/vso/v Oct. 31, 1961 R. E. JOHNSON 3,006,298

LOOP TAKERS FOR SEWING MACHINES Filed Aug. 28, 1958 2 Sheets-Sheet 2 ATTORNEY United States Patent O 3,006,298 LOP TAKERS FOR SEWING MACHINES Ralph E. Johnson, Mountainside, NJ., assignor to The Singer Manufacturing Company, Elizabeth, NJ., a corporation of New Jersey Filed Aug. 28, 1958, Ser. No. 757,798 7 Claims. (Cl. 112-192) The present invention relates to a loop taker for a sewing machine and particularly to a loop taker of the oscillating shuttle type, and has for an object to improve the hitch stitching characteristics of an oscillating shuttle.

ln accordance with the present invention, there has been provided an improved standard type oscillating shuttle mechanism in which the hitch stitching characteristics are substantially the same as that of the reverse -type shuttle mechanism.

Having in mind the above and 'other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

, FIG. 1 is -a fragmentary view partly in elevation and partly in section of a sewing machine having an oscillating shuttle mechanism in accordance with this invention.

FIG. 2 is a vertical sectional view taken substantially on the line 2-2 of FIG. 1.

FIG. 3 is an elevational view of the shuttle per se in accordance with this invention.

FIGS. 4, 5 and 6 are diagrammatic views in perspective illustrating successive stages of stitch formation with ashuttle mechanism made in accordance with this invention and with forward feed of the work. FIGS. 7, 8 and 9 are diagrammatic views in perspective similar to FIGS. 4, 5 and 6, but with reverse feed of the work.

` FIG. l0 is a schematic view illustrating the direction of feed with a standard type oscillating shuttle mechanism that will result in hitch stitching.

Y FIG. 1l is a view similar to FIG. 10, but showing the area of hitch stitching with a reverse type oscillating shuttle mechanism and a standard type oscillating shuttle mechanism in accordance with this invention.

, vWith reference to the United States patent of Hemleb, No. 1,877,757, there are two basic types of oscillating shuttle mechanisms used in sewing machines today, which for convenience, are hereinafter referred to as a standard shuttle mechanism and a reverse shuttle mechanism. -In the standard shuttle mechanism, which is illustrated in FIGS. 8 and 9 of the Hemleb patent, the needle descends on the outside of the bearing rib of the shuttle and the shuttle is moving clockwise at loop seizure. In the reverse shuttle mechanism, which is illustrated in FIGS. 6 and 7 of the Hemleb patent, the needle descends on the inside of the bearing rib of the shuttle and the shuttle is moving counterclockwise at loop seizure. With a standard shuttle, hitch stitches as distinguished from perfect lock stitches are formed as illustrated in FIG. l0, in which the direction of forward feed is indicated by thearrow F and in which the shaded area indicates the directions of feed from the point of stitch formation which will result in hitch stitches when the work is fed in any direction from the point of stitch formation within an arc of 140 extending between a line at 10 of forward feed olf the bed and a line at 40 of reverse feed up the bed. With a reverse shuttle, as illustrated in FIG. ll in which, like FIG. l0, the direction of forward feed is indicated by the Iarrow F and in which the shaded area 3,006,298 Patented Oct. 31, 1961 indicates the directions of feed hom the point of stitch formation that will result in hitch stitches, hitch stitches are formed only when the work is fed in an arc of approximately 20 up the bed and including 4 of forward feed and 16 of reverse feed. It is, of course, obvious that from the standpoint of hitch stitching, the reverse shuttle mechanism is vastly superior to the standard shuttle mechanism.

In the drawings there is illustrated a fragmentary portion of the bed plate 1, which forms a portion of the frame of a sewing machine. The bed 1 is provided with a throat plate 2 having a needle aperture 3. An endwise reciprocatory needle 4 mounted upon the end of the needle bar 5 and having a needle thread N passes through the work W and the -aperture 3 and defines the point of stitch formation on the work supporting surface of the machine. The work W is biased against the throat plate 2 by a presser foot 6 carried at the lower end of a presser bar 7. The work W is fed past the point of stitch formation by a feeding mechanism including a work engaging feed dog 8. Beneath the throat plate 2, the needle 4 cooperates in the formation of two-thread lock stitches with a loop taker mechanism of the standard oscillating shuttle type. The loop taker mechanism includes a shuttle body 9 secured by screws 10 on opposite sides thereof to lugs 11- depending from the bed plate 1. The shuttle body 9 is formed with an open-sided internal circular raceway 12 dened by a bottom wall 13 and a side wall 14, the open side vof the raceway being closed by a cap 15 resiliently held in place by a spring 16 that is secured to the body 9 by a screw 17. 'I'he shuttle 18 has a discontinuous peripheral bearing rib 19 conforming to the raceway 12 and received Within the raceway for oscillation relative thereto. 'Ihe shuttle 18 includes a back wall 20 integral with the bearing rib 19 and which has a planar central portion 21 and a smoothly curved loop deecting portion 22 that extends outwardly and transversely lof the axis of oscillation of the shuttle 18, which axis is dened by the geometrical center of the raceway 12 and is designated A in FIGS. l and 3. On the opposite side of the bearing rib 19 from the back wall 20 there is a loop deflecting front wall 23 that extends inwardly from the bearing rib 19 and diverging transversely of the axis of oscillation A of the shuttle relatively to the loop deflecting portion 22 of the back wall 20. The back wall 20 carries a bobbin-receiving post 24 that is parallel to the axis of the shuttle and which receives a thread carrying bobbin 25, FIG. 1, that is mounted within a bobbin case 26. The bobbin case 26 carries the bobbin thread tension spring 27 from beneath the end of which the bobbin thread B emerges and runs toward the point of stitch formation. The leading edge of the bearing rib 19 is cut away at an angle or beveled, as can best be seen in FIGS. 4 and 7, to form a loop seizing beak 28 having the point thereof at the outer edge of the raceway and there dening the loop seizing side of the raceway or the side upon which the needle is designed to descend. Directly behind the loop seizing beak 28 there is formed a throat 29. 'I'he opposite end of the bearing rib 19, as indicated at 30, constitutes the heel of the shuttle.

i Oscillation is imparted to the shuttle 18 by a shuttle driver 31 which is substantially U-shaped with the opposite ends thereof alternately abutting against the heel 30 and the throat 29. The shuttle driver 31 is mounted upon the end of a shuttle actuating shaft 32 that is journaled in the bed of the machine. Angular movement of the bobbin ease 26 on the post 24 is prevented by a rotation restraining nger 33, the end of which is received within a notch 34 in the shuttle body 9 so that the shuttle 18 will oscillate relatively thereto.

Being a standard type oscillating shuttle, the shuttle 18 is arranged inside of the path of reciprocation of the needle 4, or in other words, the needle `4 descends on theoutside `of, the bearing rib.19 of. the-shuttle, and it moves clockwise -at loop seizure, as indicatedV by the arrow R in FIGS. 4-9; :The side of the bearing rib I9 upon which the needle descends is distinguished by a needle clearance cutaway 35. The loop seizing beak 2K8 of the shuttle is formed with the point thereof adjacent to the path of needle reciprocation which is outside of the bearing rib. The direction of forward feed of the work, which is feeding away from the operator, is indicated by the feed arrow in FIG. 4, while the direction of reverse kfeed is indicated by the feed arrow in FIG. 7.

The structure as above described, constitutes a conventional standard type oscillating shut-tle mechanism. As noted above, during operation of such a sewing machine having this type of loop taker, hitch stitches are formed -as illustrated in FIG. in any direction of feed from the point of stitch formation within an arc of 140 between a line at 10 of forward feed olf the bed andra line at 40 of reverse feed up the bed. In thistype of mechanism, the lead of the bobbin thread B extends from the point at which it emerges from beneatl'r the-bobbin thread tension spring 27 on the bobbin case 26 across the front wall 23 of the shuttle to the point of stitch formation, and during stitch formation, the shuttle passes behindV the bobbin thread lead. It has been found that by reversing this arrangement, the hitch Ystitching characteristics of 4the machine are improved to the point where they are similar to that of a reverse type shuttle, or in other words, the directions of feed resulting in hitch stitching arereduced to an arcV of approximately 20 extending up the arm'and including 4 of forward feed and 16 of reverse feed, as illustrated in FIG. l1. More specically,.this improvement is obtained by directing the bobbin thread lead across the back wall 20 of the shuttle rather than the front wall 23, during stitch formation so that the shuttle will pass in front of the bobbin thread lead rather than behind it as heretofore.

In the illustrated embodiment of the invention, the means provided for modifying the bobbin thread lead comprises a slot 36 formed in the back wall 20 of the shuttle substantially at the juncture of the planar central portion 21 and the curved loop deflecting portion- 22. More particularly, the slot 36 is concentric of the axis about which the shuttle oscillates and is spaced from the axis A a distance at least equal to the radius of the bobbin case 26 so that, as seen in FIG. 2, the bobbin thread lead will have a minimum tortuous-path fronr the point at Vwhich it emerges from under Ythe'bobbin thread tension spring, through the slot 36, to the needle aperture 3 in -the throat plate 2 and thus to the work. Since during operation of the sewing machine, the shuttle 18 is oscillated relatively to the bobbin case 26, the ends of the slot 36 engage the bobbin thread lead as the shuttle approaches theends of its motion and pulls the thread. The pull on the bobbin thread would, of course, place an undesirable excess of bobbin thread in the system which would adversely effect stitch setting and also create a problem of controlling it. To minimize the excess thread, the slot 36 is elongated angularly and concentrically of the axis A so that the shuttle can oscillate freely relatively to the bobbin thread lead. The bobbin thread lead can accommodate some pull by the ends of the slot 36 so -the slot 36 need not be angularly equal to the arc of oscillation of the shuttle. To modify the back wall 20 of the shuttle so that the slot 36 could be made angularly equal to the arc of oscillation of the shuttle would also require an undesirable increase in the mass of the shuttle. There is, therefore, effected a compromise. The slot 36, therefore, is made as long as possible or at least as long asnecessary to avoid an intolerable slack thread condition, and which is con- 4 sistent with the required strength of the shuttle and with the end of maintaining a minimum mass of the shuttle.

In FIGS. 4, 5 and 6, there is illustrated three successive stages in the stitch forming cycle of a shuttle in accordance with this invention, and in which the work is being fed forwardly. The condition illustrated in FIG. 4 is loop seizure. The needle 4 has entered the workV to the bottom of its stroke and has risen enough to throw out a loop of needle thread N and the shuttle 18 is moving clockwise as indicated by the larrow R with the loop seizing beak 28 of the shuttle 18 entering the loop of needle thread. In FIG. 5, the shuttle Vis approaching the end of its forward motion. The needle thread loop, which is caught in the Ythroat 29, has been expanded as the shuttle advanced, and the opposite limbs thereof have been deflected by the loop deiiecting portion 22 of the back wall 20 and the front wall 23 so that they will pass over the opposite faces of the bobbin case 26. In FIG. 6, the shuttle 18 has reached the end of its forward motion and is beginning to reverse. At this time, the needle thread loop is being withdrawn. AS will be seen, the stitch that is formed is a perfect lock stitch.

In FIGS. 7, 8 and 9', there is illustrated the same three points in the stitching cycle as in FIGS. 4, 5 and 6, but with a reverse feed. From `an examination of these views, it will be seen that a perfect lock stitch is also formed when the work is fed in reverse. This is to be contrasted with a standard type shuttle mechanism which does not include the modification of the present invention, wherein, with a reverse feed, hitch stitches are formed as illustrated in FIGS. 9a, 9b and 9c of the Hemleb patent.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modiications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus described the nature of the invention, what I claim herein is:

' 1. An oscillating shuttle for a sewing machine having a discontinuous peripheral bearing rib, a loop seizing beak formed upon one end of said bearing` rib and'delining the loop seizing side of said bearing rib, means for mounting a thread carrying bobbin in said shuttle, and means for directing a bobbin thread lead from said shuttle on that side of the bearing rib opposite from said loop seizing side, said last mentioned means comprising an angularly elongated slot formed in a wall of said shuttle concentric of the axis of oscillation of said shuttle.

2. An oscillating shuttle for a sewing machine having a discontinuous peripheral bearing rib and a back wall and a front wall upon opposite sides of said bearing rib, a loop seizing beak formed upon one end of said bearing rib for seizing a needle thread loop upon the side of said bearing rib adjacent to said front wall, means for mounting a thread carrying bobbin in said shuttle, said back wall having an angularly elongated slot concentric of the axis of oscillation of said shuttle for receiving a bobbin thread lead for directing the same from the back of said shuttle.

3. An oscillating shuttle for asewing machine having a discontinuous peripheral bearing rib and a back wall and a Yfront wall upon opposite sides of said bearing rib, said bearing rib having a beveled leading edge formmg a loop seizing beak having a point at the side of said bearing rib adjacent to said front wall, means on said back wall for mounting a thread carrying bobbin in said shuttle, said back wall having an angularly elongated slot COIlCllUC Of the axis of oscillation of said shuttle' for receiving a bobbin thread lead for directing the same from the back of said shuttle.

4. In a sewing machine having a frame including a work supporting surface, an endwise reciprocatory needle movable through and thereby dening a point of stitch formation on said Work supporting surface, and an oscillating shuttle mechanism cooperating with said needle in the formation of two-thread. lock stitches, said shuttle mechanism comprising a shuttle body having an internal circular raceway, a shuttle having a discontinuous peripheral bearing rib journaled in said raceway for oscillation, a loop seizing beak upon one end of said bearing rib and formed to effect seizure of a needle thread loop upon clockwise movement of said shuttle, means for imparting oscillation to said shuttle, and means for mounting a thread carrying bobbin in said shuttle, and means for directing a bobbin thread lead from said shuttle to the point of stitch formation and relatively to the path of oscillation of said loop seizing beak to provide for movement of said loop seizing beak between the needle and the bobbin thread lead.

5. In a sewing machine having a frame including a work supporting surface, an endwise reciprocatory needle movable through and thereby defining a point of stitch formation on said work supporting surface, and an oscillating shuttle mechanism cooperating with said needle in the formation of two-thread lock stitches, said shuttle mechanism comprising a shuttle body having an internal circular raceway, a shuttle having a discontiuous peripheral bearing rib journaled in said raceway for oscillation and a front wall and a back Wall upon opposite sides of said bearing rib, said shuttle being arranged with the path of reciprocation of said needle disposed on the same side of said bearing rib as said front Wall, a loop seizing beak upon one end of said bearing rib and formed to effect seizure of a needle thread loop upon clockwise movement of said shuttle, means for imparting oscillation to said shuttle, means for mounting a thread carrying bobbin in said shuttle, and means for directing a bobbin thread lead from the back of said shuttle to the point of stitch formation to provide for movement of said loop seizing beak between the needle and the bobbin thread lead.

6. In a sewing machine having a frame including a work supporting surface, an endwise reciprocatory needle movable through and thereby defining a point of stitch formation on said work supporting surface, and an oscillating shuttle mechanism cooperating with said needle in the formation of two-thread lock stitches, said shuttle mechanism comprising a shuttle body having an internal circular raceway, a shuttle having a discontinuous peripheral bearing rib journaled in said raceway for oscillation and a front Wall and a back wall upon opposite sides of said bearing rib, said shuttle being arranged with the path of reciprocation of said needle disposed on the same side of said bearing rib as said front wall, a loop seizing beak upon one end of said bearing rib and formed to eifect seizure of a needle thread loop upon clockwise movement of said shuttle, means for imparting oscillation to said shuttle, means for mounting a thread carrying bobbin in said shuttle, and means for directing a bobbin thread lead from the back of said shuttle to the point of stitch formation to provide for movement of said loop seizing beak between the needle and the bobbin thread lead, said last mentioned means comprising an angularly elongated slot concentric of the axis of oscillation of said shuttle through which the bobbin thread lead is threaded.

7. In a sewing machine having a frame including a work supporting surface, an endwise reciprocatory needle movable through and thereby defining a point of stitch formation on said work supporting surface, and an oscillating shuttle mechanism cooperating with said needle in the formation of two-thread lock stitches, said shuttle mechanism comprising a shuttle body having an internal circular raceway, a shuttle having a discontinuous peripheral bearing rib journaled in said raceway for oscillation and a front wall and a back Wall upon opposite sides of said bearing rib, a loop seizing beak upon one end of said bearing rib and having a point at the side of said bearing rib adjacent to said front wall, means for imparting oscillation to said shuttle, means on said back wall for mounting a thread carrying bobbin, said back Wall having an angularly elongated slot concentric of the axis of oscillation of said shuttle and through which the bobbin thread is threaded for directing the same from the back of the shuttle to the point of stitch formation.

References Cited in the le of this patent UNITED STATES PATENTS 1,151,945 Hagelstein Aug. 31, 1915 1,877,757 Hemleb Sept. 20, 1932 1,988,789 Grieb Ian. 22, 1935 2,696,794 Kirsch Dec. 14, 1954 2,853,035 Johnson Sept. 23, 1958 

